Low sperm counts

Just wondering if anyone out there has ever conceived naturally with an incredibly low sperm count. My DH has his stage 3 vericocele repaired in September 2017. His analysis then was unable to be determined and about 3 months post he’s at 700,000. He needs to be at least 5m for IUI so we are most likely going to be doing IVF but we have to wait a year. Anyone have a similar story? Or recommendations on supplements? (No prescriptions unless we have to when we do IVF) thanks ladies!! 😊